Both psychogenicity and organicity have been asserted in postural tachycardia syndrome (PoTS). We studied the genesis of palpitations to dissect the biologic nature of PoTS. Eleven PoTS patients and 10 control subjects were asked to discriminate types of palpitations when supine and in response to two sympathetic stimuli [Valsalva maneuver (VM) and 10-min head-up tilt (HUT)] and one vagolytic stimulus (atropine administration). Participants rated the 10 items of the somatosensory amplification… CONTINUE READING